Flow based pressure isolation mechanism for a fluid delivery system

ABSTRACT

The fluid delivery system includes a pressurizing device for delivering a pressurized injection fluid, a low pressure fluid delivery system, and a pressure isolation mechanism adapted for fluid communication with the pressurizing device and low pressure fluid delivery system. The pressure isolation mechanism includes a housing body defining an inlet port, an isolation port, and an internal cavity, where the housing body defines a seal seat in the internal cavity between the inlet port and isolation port. A valve member is free floating in the internal cavity and is adapted to engage the seal seat. The valve member has an open position permitting fluid communication between the inlet port and isolation port, and is fluid flow responsive to fluid flow in the inlet port to engage the seal seat and attain a closed position preventing fluid communication between the inlet port and isolation port.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of Ser. No. 12/563,463, filed Sep.21, 2009, entitled “Flow Based Pressure Isolation Mechanism for a FluidDelivery System”, which is a divisional application of application Ser.No. 11/931,594, filed Oct. 31, 2007, entitled “Flow Based PressureIsolation Mechanism for a Fluid Delivery System”, which is acontinuation-in-part application of application Ser. No. 11/615,371,filed Dec. 22, 2006, now abandoned, entitled “Flow Based PressureIsolation and Fluid Delivery System Including Flow Based PressureIsolation”.

This application may contain subject matter that is related to thatdisclosed in the following co-pending applications: application Ser. No.11/551,027, filed Oct. 19, 2006 entitled “Fluid Delivery System, FluidPath Set, and Pressure Isolation Mechanism with Hemodynamic PressureDampening Correction” which is a continuation-in-part of applicationSer. No. 11/004,670, filed Dec. 3, 2004, entitled “Fluid Delivery SystemIncluding a Fluid Path Set with Sterile Check Valve Connector” which isa continuation-in-part of application Ser. No. 10/826,149, filed Apr.16, 2004, entitled “Fluid Delivery System, Fluid Path Set, SterileConnector and Improved Drip Container and Pressure Isolation Mechanism”which may contain subject matter that is related to that disclosed inthe following co-pending applications: (1) application Ser. No.10/818,748, filed on Apr. 6, 2004; (2) application Ser. No. 10/818,477,filed on Apr. 5, 2004; (3) application Ser. No. 10/326,582, filed onDec. 20, 2002; (4) application Ser. No. 10/237,139, filed on Sep. 6,2002, now U.S. Pat. No. 6,866,654; and (5) application Ser. No.09/982,518, filed on Oct. 18, 2001, now U.S. Pat. No. 7,094,216; thedisclosures of all the foregoing applications are incorporated herein byreference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention is generally directed to the delivery of fluids inmedical procedures and, more particularly, to apparatus, systems, andmethods of protecting pressure transducers used to obtain physiologicalpressure measurements during fluid delivery procedures.

2. Description of Related Art

In many medical diagnostic and therapeutic procedures, a medicalpractitioner such as a physician injects a patient with a fluid. Inrecent years, a number of injector-actuated syringes and poweredinjectors for pressurized injection of fluids, such as contrast media(often referred to simply as “contrast”), have been developed for use inprocedures such as angiography, computed tomography, ultrasound, andNMR/MRI. In general, these powered injectors are designed to deliver apreset amount of contrast at a preset flow rate.

Angiography is used in the detection and treatment of abnormalities orrestrictions in blood vessels. In an angiographic procedure, aradiographic image of a vascular structure is obtained through the useof a radiographic contrast which is injected through a catheter. Thevascular structures in fluid connection with the vein or artery in whichthe contrast is injected are filled with contrast. X-rays passingthrough the region of interest are absorbed by the contrast, causing aradiographic outline or image of blood vessels containing the contrast.The resulting images can be displayed on, for example, a video monitorand recorded.

In a typical angiographic procedure, the medical practitioner places acardiac catheter into a vein or artery. The catheter is connected toeither a manual or to an automatic contrast injection mechanism. Atypical manual contrast injection mechanism includes a syringe in fluidconnection with a catheter connection. The fluid path also includes, forexample, a source of contrast, a source of flushing fluid, typicallysaline, and a pressure transducer to measure patient blood pressure. Ina typical system, the source of contrast is connected to the fluid pathvia a valve, for example, a three-way stopcock. The source of saline andthe pressure transducer may also be connected to the fluid path viaadditional valves, again such as stopcocks. The operator of the manualcontrast injection mechanism controls the syringe and each of the valvesto draw saline or contrast into the syringe and to inject the contrastor saline into the patient through the catheter connection. The operatorof the syringe may adjust the flow rate and volume of injection byaltering the force applied to the plunger of the syringe. Thus, manualsources of fluid pressure and flow used in medical applications, such assyringes and manifolds, typically require operator effort that providesfeedback of the fluid pressure/flow generated to the operator. Thefeedback is desirable, but the operator effort often leads to fatigue.Thus, fluid pressure and flow may vary depending on the operator'sstrength and technique.

Automatic contrast injection mechanisms typically include a syringeconnected to a powered injector having, for example, a powered linearactuator. Typically, an operator enters settings into an electroniccontrol system of the powered injector for a fixed volume of contrastand a fixed rate of injection. In many systems, there is no interactivecontrol between the operator and the powered injector, except to startor stop the injection. A change in flow rate in such systems occurs bystopping the machine and resetting the injection parameters. Automationof angiographic procedures using powered injectors is discussed, forexample, in U.S. Pat. Nos. 5,460,609; 5,573,515; and 5,800,397.

The pressure transducers used with automatic contrast injectionmechanisms and manual contrast injection mechanisms used to conductfluid injection procedures such as angiographic and like procedures areextremely sensitive to even moderate pressures generated duringactivation of the syringe, so the operator must typically close a valveto isolate the pressure transducer from the fluid path when the syringeis activated to prevent damage to the pressure transducer. Specifically,many pressure transducers can be damaged if they are subjected topressures as low as about 75 psi. Because even a hand-held syringe cangenerate pressures of 200 psi or more, the isolation of the pressuretransducer is essential in order to avoid pressure transducer failure.While the syringe is not activated, the valve is usually open to monitorpatient blood pressure.

In one known arrangement, the pressure transducer and contrast injectionmechanism are connected to the catheter through a manifold. The manifoldincludes a valve which enables the injector operator to isolate thepressure transducer during the injection of the contrast solution. Thisvalve, typically a stopcock, is used to isolate the pressure transducerto prevent damage thereto. Specifically, a stopcock configuration isprovided which either allows the pressure transducer to be in fluidcommunication with the catheter or the contrast injection mechanism tobe in fluid communication with the catheter, but not both. Typically,the stopcock handle must be turned manually to switch between the twopositions. Accordingly, this configuration provided by some currentlyavailable manifolds does not allow contrast injection to be made whilethe pressure transducer is in communication with the catheter.

One problem associated with the foregoing valve-manifold design is thatthe operator often forgets to turn the stopcock back to the positionwhere the pressure transducer is in fluid communication with thecatheter. As a result, the monitoring of the vessel or artery isinterrupted for time periods longer than necessary. The monitoring ofthe vessel or artery pressure is important during almost any vascularprocedure. Accordingly, when the operator fails to turn the stopcockhandle, other members of the medical team must interrupt the operatorand tell him or her to turn the pressure transducer back on which maycause an unnecessary distraction during a delicate medical procedure.

A well-established pressure transducer protection design includes,typically, a two-pieced housing formed from generally hemisphericalmembers that form a “pressure dome” wherein a generally planar diaphragmor membrane is positioned. The diaphragm or membrane is centered withinthe housing and has a thickness that permits deflection within thehousing in response to a pressure differential within the pressure dome.Thus, the diaphragm or membrane deflects or stretches in response to apressure differential and this deflection is transmitted via a suitablepressure transmitting media in the pressure dome to the isolatedpressure transducer. Examples of the foregoing diaphragm-type pressuretransducer isolator design are disclosed in U.S. Pat. No. 4,314,480 toBecker; U.S. Pat. No. 4,226,124 to Kersten; U.S. Pat. No. 4,077,882 toGangemi; and U.S. Pat. No. 3,863,504 to Borsanyi; U.S. Pat. No.3,713,341 to Madsen et al.; and U.S. Pat. No. 3,645,139 to Zavoda, asexamples. In the non-medical area, examples of pressure isolationdevices for pressure gauges are disclosed in U.S. Pat. No. 3,207,179 toKlagues and U.S. Pat. No. 2,191,990 to Jordan.

U.S. Pat. No. 6,896,002 to Hart et al. discloses a pressure transducerprotection device particularly adapted for angiographic fluid deliverysystems. The pressure transducer protection device disclosed by thispatent is in the form of a pressure activated valve for a three-wayconnection between a catheter, an injector, and a pressure transducer.The valve includes a body that has an inlet for connection to aninjector, an outlet for connection to a catheter, and a secondaryconnection for connection to a pressure transducer. The body alsoincludes a seal seat disposed between the secondary connection in boththe inlet and the outlet. The body is flexibly connected to a plug seal.The plug seal is disposed between the seal seat in both the inlet andthe outlet. The plug seal is movable between an open position spacedapart from the seal seat and biased towards the inlet and the outlet anda closed position against the seal seat thereby isolating the secondaryconnection from both the inlet and the outlet.

Another valve used for pressure transducer protection purposes isdisclosed by U.S. Patent Application Publication No. 2006/0180202 toWilson et al. This publication discloses an elastomeric valve having avalve body with three ports including a contrast inlet port, a salineinlet and pressure transducer port, and a patient or outlet port. Thevalve body houses a disc holder and a valve disc therein. The valve discis molded of an elastomer, such as silicone rubber, with a slit in thecenter. The elastomeric disc is sandwiched between the valve body anddisc holder and is affixed therebetween at the perimeter of the disc.Such affixation may be effected by entrapment, adhesion, mechanical orchemical welding. The elastomeric valve disclosed by this publication isresponsive to pressure changes in the valve which act on the elastomericdisc.

Despite the contributions of Hart and Wilson et al., there is a generalneed for an improved pressure transducer protection device which canoperate automatically to isolate a pressure transducer used to obtainphysiological pressure measurements, particularly those pressuretransducers used in potentially damaging fluid pressure environmentssuch as angiography.

SUMMARY OF THE INVENTION

The flow-based pressure isolation techniques described herein forprotection of a pressure transducer may take the form of a flow-basedpressure isolation mechanism in one embodiment. In this embodiment, theflow-based pressure isolation mechanism comprises a housing bodydefining an inlet port, an isolation port, and an internal cavity. Thehousing body further defines a seal seat in the internal cavity betweenthe inlet port and isolation port. A valve member is disposed in theinternal cavity and is free floating in the internal cavity and adaptedto engage the seal seat. The valve member has an open positionpermitting fluid communication between the inlet port and isolationport. The valve member is fluid flow responsive to fluid flow in theinlet port to engage the seal seat and attain a closed positionpreventing fluid flow between the inlet port and isolation port. Apressure transducer is typically associated with the isolation port.

An optional flow initiating mechanism may be associated with theisolation port and is adapted to initiate flow around the valve membersuch that the valve member operates to a closed position substantiallyupon flow initiation. The flow initiating member may be disposed in alumen in fluid communication with the isolation port. The flowinitiating mechanism typically comprises a flow initiating membermaintained in the lumen by a retainer. A filter may be disposed in abore in the retainer. The bore is in fluid communication with theisolation port and the filter is generally adapted to prevent air fromentering the internal cavity when wetted with fluid. In anothervariation, the housing body further defines a second seal seat radiallyoutward and concentric to the first seal seat.

In one form, the valve member may comprise a disk member. The valvemember may comprise a stiffening element associated with the diskmember. In one form, the stiffening element may be cylindrical shaped.In other forms, the valve member may comprise a ball member. The diskmember may be formed of compliant material. The compliant material isdesirably selected to transmit hemodynamic pressure signals through thevalve member to a pressure transducer associated with the isolationport.

One or both of the valve member and internal cavity may be shaped topermit fluid flow between the inlet port and isolation port in the openposition and prevent fluid flow between the inlet port and isolationport in the closed position. Moreover, a volumetric capacitance elementmay be disposed in the internal cavity.

Another embodiment disclosed herein relates to a fluid delivery systemthat includes flow-based pressure isolation of a pressure transducer.Such a system comprises a pressurizing device for delivering apressurized injection fluid, a low pressure fluid delivery system, and apressure isolation mechanism adapted for fluid communication with thepressurizing device and low pressure fluid delivery system. The pressureisolation mechanism comprises a housing defining an inlet port, anisolation port, and an internal cavity. The housing defines a seal seatin the internal cavity between the inlet port and isolation port. Avalve member is disposed in the internal cavity. The valve member isfree floating in the internal cavity and is adapted to engage the sealseat. The valve member has an open position permitting fluidcommunication between the inlet port and isolation port, and is fluidflow responsive to fluid flow in the inlet port to engage the seal seatand attain a closed position preventing fluid flow between the inletport and isolation port. The inlet port may be in fluid communicationwith the pressurizing device and low pressure fluid delivery system viaa fitting.

In the fluid delivery system, an optional flow initiating mechanism maybe associated with the isolation port and is adapted to initiate flowaround the valve member such that the valve member operates to a closedposition substantially upon flow initiation. The flow initiating membermay be disposed in a lumen in fluid communication with the isolationport. The flow initiating mechanism typically comprises a flowinitiating member maintained in the lumen by a retainer. A filter may bedisposed in a bore in the retainer. The bore is in fluid communicationwith the isolation port and the filter is generally adapted to preventair from entering the internal cavity when wetted with fluid. In anothervariation, the housing body further defines a second seal seat radiallyoutward and concentric to the first seal seat.

The inlet port may be in fluid communication with the pressurizingdevice and the housing body and further define a low pressure fluid portconnected to the low pressure fluid delivery system. The low pressurefluid port is in fluid communication with the isolation port and isisolated from the inlet port in the closed position of the valve member.A valve arrangement may be associated with the low pressure fluid portfor regulating fluid flow through the low pressure fluid port. The valvearrangement in one form may comprise a disk valve defining one or morepassageways regulating fluid flow through the low pressure fluid port.

In one form, the valve member for the pressure isolation mechanismassociated with the fluid delivery system may comprise a disk member. Inone form, the stiffening element may be cylindrical shaped. In otherforms, the valve member may comprise a ball member. The disk member maybe formed of compliant material. The compliant material is desirablyselected to transmit hemodynamic pressure signals through the valvemember to a pressure transducer associated with the isolation port.

One or both of the valve member and internal cavity may be shaped topermit fluid flow between the inlet port and isolation port in the openposition and prevent fluid flow between the inlet port and isolationport in the closed position. Moreover, a volumetric capacitance elementmay be disposed in the internal cavity.

The protection of a pressure transducer may take the form of a method inanother embodiment disclosed herein. The flow-based pressure isolationmethod protects a pressure transducer from fluid pressure damage usingthe pressure isolation mechanism summarized hereinabove. The pressureisolation mechanism comprises an inlet port, an isolation port, and aninternal cavity wherein a free floating, fluid flow responsive valvemember is disposed and adapted to engage a seal seat in the internalcavity. An optional flow initiating mechanism may be associated with theisolation port. The method generally comprises associating the pressuretransducer with the isolation port; placing a pressurizing device fordelivering fluid under pressure in fluid connection with the inlet port;actuating the pressurizing device to cause fluid flow in the inlet portsuch that the free floating, fluid flow responsive valve member engagesthe seal seat to attain a substantially closed position and preventfluid flow between the inlet port and isolation port. In a variation ofthe foregoing method, upon actuation of the pressure device, the flowinitiating mechanism may initiate flow around the valve member such thatthe valve member operates to the closed position substantially upon flowinitiation.

The method may further comprise deactuating the pressurizing device andallowing the valve member to attain an open position disengaged from theseal seat permitting fluid communication between the inlet port andisolation port.

As part of the method hemodynamic pressure signals may be read with thepressure transducer, with the signals transmitted via the fluidcommunication between the inlet port and isolation port in the openposition of the valve member. The hemodynamic pressure signals may evenbe read with the pressure transducer in the substantially closedposition of the valve member by being transmitted at least in partthrough the body of the valve member, typically having at least aportion thereof formed on compliant material.

The pressure isolation mechanism may further comprise a low pressurefluid port connected to a low pressure fluid delivery system, the lowpressure fluid port in fluid communication with the isolation port andisolated from the inlet port in the closed position of the valve member.The method may further comprise isolating the low pressure fluiddelivery system from hemodynamic blood pressure signals with a valvearrangement in the low pressure fluid delivery port.

Further details and advantages will become clear upon reading thefollowing detailed description in conjunction with the accompanyingdrawing figures, wherein like parts are identified with like referencenumerals throughout.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a fluid delivery system including afluid path set that utilizes flow-based pressure isolation for theprotection of a pressure transducer.

FIG. 2A is a perspective view of a portion of the fluid path set used inthe fluid delivery system of FIG. 1 and which incorporates a flow-basedpressure isolation mechanism.

FIG. 2B is a side and partially perspective view of the complete fluidpath set used in the fluid delivery system of FIG. 1.

FIG. 3 is a perspective view of a first embodiment of the flow-basedpressure isolation mechanism incorporating a flow-responsive valvemember in the form of a flow-responsive disk valve member.

FIG. 4 is an exploded perspective view of the flow-based pressureisolation mechanism of FIG. 3.

FIG. 5 is a transverse cross-sectional view of the flow-based pressureisolation mechanism of FIG. 3 showing the disk valve member in an openposition.

FIG. 6 is a transverse cross-sectional view of the flow-based pressureisolation mechanism of FIG. 3 showing the disk valve member in a closedposition.

FIG. 7 is a transverse cross-sectional view of the flow-based pressureisolation mechanism of FIG. 3 incorporating an alternativebi-directional flow-responsive valve member.

FIG. 8 is a perspective view of a third embodiment of the flow-basedpressure isolation mechanism incorporating a flow-responsive valvemember in the form of a flow-responsive ball valve member.

FIG. 9 is an exploded perspective view of the flow-based pressureisolation mechanism of FIG. 8.

FIG. 10 is a transverse cross-sectional and partially perspective viewof the flow-based pressure isolation mechanism of FIG. 8 showing theball valve member and internal details of the mechanism.

FIG. 11 is a transverse cross-sectional view of the flow-based pressureisolation mechanism of FIG. 8 showing the ball valve member in an openposition.

FIG. 12 is a transverse cross-sectional view of the flow-based pressureisolation mechanism of FIG. 8 showing the ball valve member in a closedposition.

FIG. 13 is an exploded perspective view of a fourth embodiment of theflow-based pressure isolation mechanism incorporating a flow-responsivevalve member in the form of a flow-responsive cylinder valve member.

FIG. 14 is a transverse cross-sectional and partially perspective viewof the flow-based pressure isolation mechanism of FIG. 13 showing theflow-responsive cylinder valve member and internal details of themechanism.

FIG. 15 is a transverse cross-sectional view of the flow-based pressureisolation mechanism of FIG. 13 showing the cylinder valve member in anopen position.

FIG. 16 is a transverse cross-sectional view of the flow-based pressureisolation mechanism of FIG. 13 showing the cylinder valve member in aclosed position.

FIG. 17 is a perspective view of a fifth embodiment of the flow-basedpressure isolation mechanism having two inlet ports for different fluidsand incorporating a flow-responsive valve member in the form of aflow-responsive disk valve member.

FIG. 18 is a cross-sectional view taken along lines 18-18 in FIG. 17.

FIG. 19 is a cross-sectional view of the flow-based pressure isolationmechanism of FIG. 17 showing the disk valve member in an open position.

FIG. 20 is a cross-sectional view of the flow-based pressure isolationmechanism of FIG. 16 showing the disk valve member in a closed position.

FIG. 21 is a partial cross-sectional view of the flow-based pressureisolation mechanism of FIG. 17 illustrating a valve arrangement adaptedto provide hemodynamic pressure dampening correction.

FIGS. 22A-22C are perspective views of respective embodiments of anelastomeric disk valve associated with the valve arrangement of FIG. 21.

FIG. 23 is a perspective view of a sleeve adaptor used to associate theelastomeric disk valve with the flow-based pressure isolation mechanism.

FIG. 24 is a perspective view of a distal end of the sleeve adaptor ofFIG. 23.

FIG. 25 is a cross-sectional view of a sixth embodiment of theflow-based pressure isolation mechanism incorporating a flow-responsivevalve member in the form of a flow-responsive disk valve member and avolumetric capacitance element in the isolation port.

FIG. 26 is a perspective view of another embodiment of the flow-basedpressure isolation mechanism incorporating a flow-responsive valvemember in the form of a flow-responsive disk valve member.

FIG. 27 is a transverse cross-sectional view of the flow-based pressureisolation mechanism of FIG. 26 showing the disk valve member in a closedposition and the flow-based pressure isolation mechanism associated withan element of the fluid path set of FIGS. 1 and 2A-2B.

FIG. 28 is a transverse cross-sectional view of a portion of theflow-based pressure isolation mechanism of FIG. 26 illustrating a flowinitiating mechanism.

FIG. 29 is an exploded perspective view of the flow-based pressureisolation mechanism of FIG. 26 including the flow initiating mechanism.

FIG. 30 is a cross-sectional view of a variation of the flow initiatingmechanism shown in FIGS. 27-29.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

For purposes of the description hereinafter, spatial orientation terms,if used, shall relate to the referenced embodiment as it is oriented inthe accompanying drawing figures or otherwise described in the followingdetailed description. However, it is to be understood that theembodiments described hereinafter may assume many alternative variationsand configurations. It is also to be understood that the specificdevices illustrated in the accompanying drawing figures and describedherein are simply exemplary and should not be considered as limiting.

A fluid injector or delivery system 12 is illustrated generally in FIG.1 and includes flow-based pressure isolation techniques for theprotection of a pressure transducer P (FIG. 2A) used to take hemodynamicpressure readings during a fluid injection or delivery procedure. Fluiddelivery system 12 includes, generally, a fluid injector 14 operativelyassociated with a fluid control module 16. The details of fluid injector14 are set forth in co-pending U.S. patent application Ser. No.10/818,477, the disclosure of which was incorporated herein by referencepreviously. Fluid injector 14 is adapted to support and actuate a fluiddelivery syringe, as described herein in connection with FIG. 2B. Fluidcontrol module 16 is associated with fluid injector 14 for controllingfluid flows delivered by the fluid injector 14. The details of fluidcontrol module 16 are set forth in U.S. patent application Ser. No.10/826,149, incorporated herein by reference previously. Fluid controlmodule 16 is generally adapted to support and control a fluid path set18 used to connect a syringe associated with fluid injector 14 to acatheter (not shown) to be associated with a patient. Fluid injector 14and a syringe associated therewith serve as a pressurizing device forpressurizing fluid, such as contrast media (“contrast”), to be injectedinto a patient via the catheter. As an example, fluid injector 14 may beused as a vehicle to inject contrast at high fluid pressure into a bloodvessel of a patient undergoing angiography. Additionally, fluid deliverysystem 12 includes a user-input control section or device 20 forinterfacing with computer hardware/software (i.e., electronic memory) offluid control module 16 and/or fluid injector 14, the details of whichare identified in the foregoing Applications incorporated by reference.While the details of fluid control module 16 are set forth in detail inU.S. patent application Ser. No. 10/826,149, fluid control module 16generally includes a housing unit supporting a valve actuator 22 forcontrolling a fluid control valve, such as a three-way stopcock, a fluidlevel sensing mechanism 24, a peristaltic pump 26, an automatic shut-offor pinch valve device 28, and an air detector assembly 30.

Referring additionally to FIGS. 2A-2B, fluid control module 16 isgenerally adapted to support and control fluid flow through fluid pathset 18 used to connect a syringe 32 associated with fluid injector 14 toa catheter (not shown) inserted in a patient. Fluid path set (“fluidpath 18”) may be considered to include syringe 32 that is associatedwith front-load fluid injector 14. Fluid path 18 is generally used toassociate syringe 32 with a first or primary source of injection fluid34, such as contrast, provided in a conventional medical container,which will be loaded into syringe 32 for a fluid injection procedure.First or primary fluid source 34 may be contrast in the case ofangiographic or computed tomography procedures, as examples. Fluid path18 is further adapted to associate syringe 32 with a secondary oradditional source of fluid 36 also provided in a conventional medicalcontainer, which is to be supplied or delivered to the patient via thecatheter. In a typical fluid delivery procedure, whether angiography orcomputed tomography, saline is often used as a secondary flushing fluidwhich is supplied to the patient between injections of contrast forclearing the catheter or clearing fluid path 18 of contrast, etc.

In a general fluid injection procedure involving fluid delivery system12, fluid injector 14 is filled with fluid from primary fluid source 34and delivers this fluid via fluid path 18 to the catheter and,ultimately, the patient. Fluid control module 16 generally controls ormanages the delivery of the injection fluid through a control valve,such as a three-way stopcock, associated with fluid path 18 which iscontrolled or actuated by valve actuator 22 on the fluid control module16. Fluid control module 16 is further adapted to deliver fluid from thesecondary fluid source 36 under pressure via peristaltic pump 26associated with the fluid control module 16. In a typical fluidinjection procedure, valve actuator 22 actuates a valve, such as athree-way stopcock, associated with fluid path 18 which alternatelypermits fluid from the first or primary fluid source 34 to be loaded tosyringe 32 associated with fluid injector 14 and then placed in a stateto allow fluid communication or connection between syringe 32 anddownstream portions of the fluid path 18 for delivering fluid such ascontrast to the catheter connected to the fluid path 18. In a typicalangiographic procedure as an example, fluid injector 14 may pressurizethe contents of syringe 32 to pressures exceeding 1200 psi. Thus, fluidinjector 14 and syringe 32 form a pressurizing device capable ofproviding contrast and like injection fluids to a patient under highpressure via fluid path 18 which is ultimately connected to anindwelling catheter inserted into a blood vessel of the patient.Peristaltic pump 26 and secondary fluid source 36 form a low pressurefluid delivery system 38 which provides a secondary injection fluid suchas saline via the fluid path 18 to the patient and primarily forflushing the fluid path 18 and the catheter inserted in the patient, asindicated previously.

Fluid path 18 is generally comprised of a first section or portion 40and a second section or portion 42. First section 40 is generallyadapted to connect syringe 32 to the primary fluid source 34 and thesecond section 42, and to connect the second section 42 to the secondaryfluid source 36. First section 40 may be used as a multi-patient sectionor set disposed of after a preset number of fluid injection proceduresare accomplished with fluid delivery system 12. Thus, first section 40may be used for a preset number of fluid injection procedures involvingone or more patients and may then be discarded. Optionally and lessdesirably, first section 40 may be adapted to be re-sterilized forreuse. First section 40 is provided as a sterile set typically in asterile package. Second section 42 is intended as a per-patient sectionor set which is disposed of after each fluid injection procedureinvolving fluid delivery system 12. First section 40 and second section42 are placed in fluid communication by use of one or more connectors44, the details of which are set forth in U.S. patent application Ser.No. 11/551,027 previously incorporated by reference.

First section 40 includes a multi-position valve 46 such as a three-waystopcock valve which is adapted to be automatically controlled oractuated by valve actuator 22 associated with fluid control module 16.In general, multi-position valve 46 may be actuated by valve actuator 22to selectively isolate the syringe 32 and the primary fluid source 34from the remainder of fluid path 18 and place the syringe 32 in fluidconnection with the primary fluid source 34. This selectively allowsfluid injector 14 to fill syringe 32 with fluid from primary fluidsource 34, deliver fluid loaded into syringe 32 to fluid path 18 underpressure while isolating the primary fluid source 34, or isolate thesyringe 32 and primary fluid source 34 from the remainder of the fluidpath 18.

First section 40 includes intervening drip chambers 48 associated withthe primary fluid source 34 and secondary fluid source 36. It ispossible to replace drip chambers 48 with priming bulbs (not shown) influid path 18, if desired. Drip chambers 48 are adapted to be associatedwith the containers forming primary and secondary fluid sources 34, 36with conventional spike members 50. Fluid level sensing mechanism 24 onfluid control module 16 is used to sense fluid levels in drip chambers48 when fluid path 18 is associated with fluid injector 14 and fluidcontrol module 16. Generally, operation of fluid delivery system 12includes loading syringe 32 with fluid from the primary fluid source 34,which passes to the syringe 32 via the drip chamber 48 associated withthe primary fluid source 34. Similarly, during operation of fluiddelivery system 12 fluid, such as saline, from the secondary fluidsource 36 is supplied to fluid path 18 via the drip chamber 48associated with the secondary fluid source 36. Drip chambers 48 aregenerally adapted to permit fluid level sensors associated with fluidlevel sensing mechanism 24 to detect the level of fluid in the dripchambers 48, for example, by using optical or ultrasonic methods.

Respective output lines 52 made, for example, of conventional lowpressure medical tubing, are associated with drip chambers 48 forconnecting the drip chambers 48 to multi-position valve 46 and secondsection 42 of fluid path 18, respectively. An output line 54 frommulti-position valve 46 connects the multi-position valve 46 and syringe32 to second section 42 of fluid path 18 via connector 44. Due to thehigh injection pressures typically generated by fluid injector 14 duringa fluid injection procedure such as angiography, output line 54 isdesirably a high pressure medical tubing line. Additionally, aconnecting tubing line 56 connecting multi-position valve 46 and syringe32 is also desirably a high pressure medical tubing line to withstandthese high fluid injection pressures.

A pressure isolation mechanism 100 is provided as part of fluid path 18and the disposable second section 42 thereof in particular. Pressureisolation mechanism 100 serves several functions in fluid deliverysystem 12 but is primarily provided to connect the pressure transducer Pto fluid path 18 so that hemodynamic blood pressure signal readings maybe obtained during fluid delivery procedures involving fluid deliverysystem 12. In certain embodiments described herein (FIGS. 17-20 as anexample), this mechanism may serve as a physical merge point for theprimary and secondary injection fluid paths, such as contrast andsaline, for delivery to a patient during a fluid injection or deliveryprocedure via a catheter. Due to the need to protect pressure transducerP from damaging fluid pressure, which can occur at fluid pressure as lowas about 75 psi and higher as indicated previously, pressure isolationmechanism 100 includes internal valve structure that provides automaticoverpressure protection for pressure transducer P during fluid deliveryprocedures, particularly those associated with the delivery of contrastat high pressure during angiographic procedures. Further details ofpressure isolation mechanism 100 are provided hereinafter.

Pressure isolation mechanism 100 is typically associated with secondsection 42 of fluid path 18 via a Y-T fitting 58 having two input ports60, 62 respectively connected to input lines 64, 66. Y-T fitting 58 inthis embodiment and other embodiments discussed hereinafter serves asthe merge point for the primary and secondary injection fluid paths,such as contrast and saline, for delivery to a patient via a catheterduring a fluid injection or delivery procedure. Input lines 64, 66comprise a first input line 64 associated with the low pressure fluiddelivery system 38 generally and output line 52 connected to dripchamber 48 associated with the secondary fluid source 36 in particular,and a second input line 66 associated with the high pressure system ordevice comprised by syringe 32 and fluid injector 14. This high pressureside of the fluid path 18 is alternately placeable in fluidcommunication with output line 52 connected to the drip chamber 48associated with the primary fluid source 34 as described previously tofill syringe 32 with primary injection fluid, typically contrast. Bothfirst input line 64 and the upstream output line 52 associated withsecondary fluid source 36 are desirably high pressure medical tubinglines to avoid any damage to the first input line 64 and upstream outputline 52 from high backpressure through the Y-T fitting 58. However, withthe addition of a check valve in input port 60 of Y-T fitting 58,conventional low pressure medical tubing may be used for first inputline 64 and upstream output line 52. Alternatively, first input line 64could be made of high pressure medical tubing line and upstream outputline 52 made of low pressure medical tubing with the addition of a checkvalve associated with the connector 44 used to connect first input line64 to upstream output line 52 to isolate output line 52 from highbackpressure through Y-T fitting 58. Similarly, second input line 66 isdesirably formed of high pressure medical tubing and connects secondinput port 62 with output line 54 connected to multi-position valve 46and, thereby, syringe 32. While Y-T fitting 58 is a convenient device tomerge the primary and secondary fluid paths its presence in fluid path18 is only exemplary and other merging arrangements may be used in placeof Y-T fitting 58 as evidenced by the arrangement illustrated in FIGS.17-20.

Y-T fitting 58 further comprises a pressure transducer port 68 forassociating the pressure isolation mechanism 100 with fitting 58, and anoutlet port 70. A multi-position valve 72, such as three-way stopcock,is connected to outlet port 70 and may used as a simple shut-off valveto isolate the catheter (not shown) from fluid path 18. A catheterconnection line 74 terminating in a luer connector 76 is associated withmulti-position valve 72. One of the ports of the multi-position valve 72may be a waste port 78 and the remaining port comprises an outlet port80 that is configured with a luer connector 82 for associating catheterconnection line 74 to multi-position valve 72 and, thus, fluid path 18.

Referring additionally to FIGS. 3-5, pressure isolation mechanism 100according to one embodiment is shown. Pressure isolation mechanism 100includes a housing body 102 which may be unitary or desirably providedas a two-piece structure including a first or upper housing portion 104and a second or lower housing portion 106, which are adapted to connecttogether to form the housing body 102. As an example, first and secondhousing portions 104, 106 may be formed for interference engagement witheach other and sealed through the use of a medical grade adhesive, orsolvent, laser, or ultrasonic weld. Such an interference engagement isformed in part by engagement of a depending outer annular rim 108 formedon first housing portion 104 with a corresponding recess or groove 110,for example, a circumferential or perimetric recess or groove, formed ordefined in the second portion 106. Groove 110 may purposely be madeslightly smaller in width than the thickness of outer annular rim 108 sothat when the first and second housing portions 104, 106 of housing body102 are joined together there is interference engagement between theouter annular rim 108 and groove 110. Additional interference engagementmay be provided between the first and second housing portions 104, 106of housing body 102 may be accomplished by providing the second housingportion 106 of housing body 102 with a raised inner annular rim 112 thatengages or cooperates with a corresponding recess or groove 114,typically a circumferential or perimetric recess or groove, defined inthe first housing portion 104. Raised inner annular rim 112 may engagewith groove 114 in a similar friction fit—interference engagement manneras outer annular rim 108 cooperates or engages groove 110 in the secondhousing portion 106 of housing body 102 discussed previously. Thecombination of the annular rims 108, 112 and grooves 110, 114 generallydefine a shear interface 116 between the first and second housingportions 104, 106 of housing body 102 which increases their assemblystrength. An adhesive, solvent, laser, or ultrasonic weld may be usedalong shear interface 116 to secure first and second housing portions104, 106 together. The connection between annular rims 108, 112 andgrooves 110, 114 generally defines a tortuous path along this connectionline.

First and second housing portions 104, 106 of housing body 102, whensecured together, define an internal chamber or cavity 118. Housing body102 further includes an inlet port 120 in the lower or second housingportion 106 which communicates with internal cavity 118 and an isolationport 122 in the first or upper housing portion 104 also in fluidcommunication with the internal cavity 118. As illustrated, inlet port120 and isolation port 122 may be formed as standard luer connectors. Inthe illustrated embodiment, inlet port 120 is shown as a standard maleluer while isolation port 122 is shown as a female luer for exemplarypurposes only and this configuration may be reversed. As is apparentfrom FIG. 2A, inlet port 120 is adapted for connection to pressuretransducer port 68 on fitting 58 to associate pressure isolationmechanism 100 with fitting 58 and, thus, fluid path 18. Isolation port122 is adapted to engage pressure transducer P to fluidly connect thepressure transducer P to fluid path 18. First or upper housing portion104 defines a seal seat or rim 124 internally within internal cavity 118that is generally circular in configuration but may take other suitableforms. Generally, seal seat 124 is a raised continuous lip or rimagainst which a valve element or structure may make a sealing connectionor engagement. Seal seat 124 is provided in internal cavity 118 betweeninlet port 120 and isolation port 122. A valve member 126 is disposedwithin the internal cavity 118 between inlet port 120 and isolation port122. Valve member 126 is adapted to engage and seal against seal seat124 but is disposed within the internal cavity 118 to be free-floatingtherein. By free-floating it is generally meant that valve member 126 isfreely movable within internal cavity 118 in response to fluid flow intoinlet port 120 so that the valve member 126 may engage and seal againstseal seat 124 to close off fluid flow through internal cavity 118thereby isolating isolation port 122. Accordingly, valve member 126 isin no way biased in internal cavity 118.

In one form, valve member 126 is generally disk-shaped with thedisk-shaped valve member 126 comprised of a disk-shaped member 128formed of compliant material, such as rubbers or thermoplasticelastomers or silicone, and a stiffening element 130 which is desirablyintegrally formed with disk member 128 or otherwise secured in permanentor semi-permanent fashion with disk member 128 such as by an adhesive.Stiffening element 130 is desirably formed of a harder plastic materialsuch as polypropylene, polyethylene, or polycarbonate as examples and issuited for supporting disk member 128 which is adapted to seat and sealin engagement with seal seat 124 to seal inlet port 120 from isolationport 122. In operation, valve member 126 is responsive to fluid flow ininlet port 120 so that the valve member 126 may seat and seal againstseal seat 124 to form a closed state or condition of pressure isolationmechanism 100. When valve member 126 is not seated against seal seat124, valve member 126 defines an open state or condition of the pressureisolation mechanism 100. Desirably, the fluid flow in inlet port 120needed to cause valve member 126 to seat and seal against seal seat 124and thereby attain a closed state is very small and valve member 126will seat and seal against seal seat 124 in a near statically closedsystem due to very small compliance of the pressure transducer P andconnecting tubing T associated therewith connected to isolation port122. This small volume compliance associated with the pressuretransducer P and connecting tubing T associated therewith connected toisolation port 122 as well as in the upper portion of internal cavity118 above valve member 126 is provided or is needed to cause enoughforward flow in inlet port 120 to seat the valve member 126 against theseal seat 124 and close the valve member 126.

In addition, this small volume capacitance generates reverse fluid flowin the isolation port 122 that unseats valve member 126 from seal seat124 when fluid injections are not occurring thereby “opening” thepressure isolation mechanism 100 after a fluid injection procedure. Tostate the foregoing in another way, the small volume capacitance ofpressure transducer P and connecting tubing T generates reverse fluidflow in isolation port 122 and the upper portion of internal cavity 118above disk member 128 that unseats valve member 126 from seal seat 124when fluid flow in inlet port 120 is discontinued. Sufficient fluid flowis typically present in inlet port 120 to seat and seal valve member 126against seal seat 124 when a fluid injection procedure begins usingfluid injector 14 and syringe 32 due to this same small volumecapacitance and, when fluid injection is complete, flow ceases allowingvalve member 126 to unseat from seal seat 124 due to the reverse flowgenerated by this small volume capacitance upstream of isolation port122 provided by pressure transducer P and connecting tubing T and thatassociated with isolation port 122 and the upper portion of internalcavity 118 as well. If the low pressure side of valve member 126,namely, isolation port 122 and pressure transducer P and connectingtubing T, is too ridged then a pressure relief valve 123 could beincorporated into first or upper housing portion 104 to initiate flowand close the valve member 126, or tubing T could be semi-compliantmember to allow fluid flow to initiate (in both directions).

As shown in FIGS. 5-6, stiffening element 130 is generally positioned inassociation with disk member 128 to support disk member 128 such thatthe disk member 128 may form a fluid seal with seal seat 124 to closeoff fluid flow to isolation port 122 when fluid flow is present in inletport 120. Moreover, stiffening element 130 includes a top side 131 and abottom side 132. Structures are provided on the bottom side 132 ofstiffening element 130 that face inlet port 120 which prevent the valvemember 126 and stiffening element 130, in particular, from forming aseal with the interior of second portion 106 of housing body 102. Suchstructures located on the bottom side 132 of stiffening element 130 maybe in the form of a series of tab members 134 on the bottom side 132which prevent the stiffening element 130 from collapsing onto an innersurface 136 of the lower or second housing portion 106 of housing body102, potentially forming a seal with inner surface 136. As FIGS. 5-6further show, internal cavity 118 and valve member 126 are desirablyformed without sharp corners, trapping recesses, or acute angles tominimize the possibility of forming air bubble trap locations ininternal cavity 118 which can affect the accuracy of hemodynamicpressure signal readings taken by pressure transducer P as discussedhereinafter. It is noted that the choice of placing tab members 134 onthe bottom side of stiffening element 130 (or as part of valve member126 generally) or forming the same as part of the inner surface 136 ofthe lower or second housing portion 106 of housing body 102 is a matteronly of design choice, and either configuration may be used in any ofthe embodiments of this disclosure.

Additionally, in the open position or state of valve member 126 fluidcommunication is present between inlet port 120 and isolation port 122,as shown in FIG. 5, which permits hemodynamic pressure signals to passvia the fluid communication to the pressure transducer P associated withisolation port 122. As described hereinabove, in the closed position ofvalve member 126, disk member 128 seats against seal seat 124. This mayoccur, as indicated previously, when fluid flow is present in inlet port120. However, this may also occur when the pressure isolation mechanism100 is substantially inverted (i.e., turned upside down) from theorientation shown, for example, in FIG. 5. In this orientation, valvemember 126 moves to the closed position under the force of gravity anddisk member 128 seats against seal seat 124. Even in this closedposition or state of valve member 126, the compliant material thatdesirably forms disk member 128 allows hemodynamic pressure signals tobe transmitted through the body of valve member 126 to pressuretransducer P. Thus, it is possible to take accurate hemodynamic pressuresignal readings with pressure transducer P in the closed position (asjust described) and the open position of pressure isolation mechanism100 as defined by valve member 126 when a fluid injection procedure isnot ongoing. Nonetheless, pressure transducer P remains protected fromdamaging fluid pressure present at inlet port 120 when a fluid injectionprocedure commences due to the free-floating, flow-based sealing actionof valve member 126.

An advantage of pressure isolation mechanism 100 described hereinaboveis that highly accurate hemodynamic pressure signal readings areobtained due to the minimal volume capacitance present in pressuretransducer P and connecting tubing T upstream of isolation port 122, aswell as in the volume of the isolation port 122 and upper portion ofinternal cavity 118. Applicants have determined that volume capacitanceor termed differently volume compliance in fluid path 18 has an effecton the accuracy of the hemodynamic pressure signal readings taken bypressure transducer P. Volume capacitance or compliance may be describedas the change in volume or “swelling” induced in the components fluidpath 18 when under system pressure. In fluid path 18, the componentswhich have the greatest effect on the accuracy of the hemodynamicpressure signal readings taken by pressure transducer P are theconnecting tubing T and the volume displacement of pressure transducer Pitself. Due to the small or minimized volume capacitance of thesecomponents and, further, the small volume capacitance or compliance ofisolation port 122 and the upper portion of internal cavity 118 highlyaccurate hemodynamic pressure signal readings may be taken by thepressure transducer P. Applicants have further determined that numerousvariables affect volume compliance or capacitance characteristics of afluid injection system. These variables include, but are not limited to:tubing size, material resiliency/rigidity, viscosity of fluid in thesystem, length of fluid travel, and foreign materials present in thefluid including air bubbles. Volume compliance or capacitance may bekept to minimum by limiting tubing size, using more robust materials forsystem components, limited fluid travel length, and removing foreignmatter particularly air bubbles from the fluid path. The short length ofconnecting tubing T, the rigidity of the material forming housing body102, and small volume displacement of pressure transducer P limit thevolume capacitance or compliance so that accurate hemodynamic pressuresignal readings are possible. However, as described previously, somevolume capacitance or compliance is provided or is needed first to causeenough forward flow in inlet port 120 to close the valve member 126 whena fluid injection procedure commences and, further, to cause enoughreverse fluid flow in isolation port 122 and the upper portion ofinternal cavity 118 to open valve member 126 after a fluid injectionprocedure is complete. Therefore, it is undesirable in one context ofpressure isolation mechanism 100 to completely eliminate the volumecapacitance or compliance associated with isolation port 122 but it isdesirable to limit this characteristic to that needed to allow properfunctioning of valve member 126, which is to close when a fluidinjection procedure commences and open when a fluid injection procedurehas been completed or fluid injection ceases for any reason. Theforegoing discussion relative to volume capacitance or compliance isapplicable to any of the embodiments of pressure isolation mechanism 100described in this disclosure.

Another embodiment of pressure isolation mechanism 100 a is shown inFIG. 7 which is substantially similar in construction to pressureisolation mechanism 100 discussed hereinabove but does not allow freeflow of fluid in either direction through internal cavity 118 a. In thisembodiment, a cap structure 143 is provided as discussed herein to holdthe valve member 118 a in an open position wherein the valve member 118a does not seat against seal seat 124 a to allow purging of air frompressure isolation mechanism 100 a prior to using pressure isolationmechanism 100 a in fluid path 18. Cap member or structure 143 and itsassociated use in purging air from the pressure isolation mechanism 100a are described herein. To prevent free flow of fluid in eitherdirection through pressure isolation mechanism 100 a, the inner surface136 a of the second or lower housing portion 106 a of housing body 102 ais formed with an opposing seal seat 124 a(2) opposite from seal seat124 a(1) and in place of tab members or structures 134 describedpreviously. Second seal seat 124 a(2) is similar in shape andconstruction to first seal seat 124 a(1) and is adapted to coact orengage with the bottom side of valve member 126 a to form a fluid sealtherewith thereby preventing reverse flow through internal cavity 118 a.

In pressure isolation mechanism 100 a, it will be noted that stiffeningelement 130 a of valve member 126 a is formed with opposing projections140, 142 extending from top and bottom sides 131 a, 132 a, respectively,of stiffening element 130 a that project within internal cavity 118 atoward inlet port 120 a and isolation port 122 a. Second or lowerhousing body portion 106 a defining inlet port 120 a is elongatedslightly so that the length of internal cavity 118 a is extended along acentral axis of housing body 102 a. This slight extension of internalcavity 118 a accommodates lower extension 142 as illustrated.Additionally, compliant material similar to that used to form diskmember 128 described previously encapsulates top and bottom sides 131 a,132 a of stiffening element 130 a and this compliant encapsulating layeris designated with reference numeral 128 a. As FIG. 7 shows, stiffeningelement 130 a is not encapsulated in areas on the top and bottom sides131 a, 132 a of stiffening element 130 a where projections 140, 142 areprovided. From the encapsulated form of stiffening element 130 a shownin FIG. 7, it is clear that the encapsulated stiffening element 130 a ineffect provides opposite facing disk-shaped members 128 a on the top andbottom sides 131 a, 132 a of stiffening element 130 which are analogousto disk member 128 described previously for engaging the respectivefirst and second seal seats 124 a(1), 124 a(2) to form seals therewith.As a result, valve member 126 a is capable of preventing free flow offluid in either direction through internal cavity 118 a.

This embodiment of pressure isolation mechanism 100 a operates in thesame manner described previously to protect pressure transducer P duringa fluid injection procedure. In particular, during a fluid injectionprocedure valve member 126 a is subjected to forward flow in inlet port120 a and closes in the manner described previously to protect pressuretransducer P from high pressures during the injection. Additionally,this embodiment of pressure isolation mechanism 100 a also protects thepressure transducer P from a potentially damaging vacuum condition whichcan occur during the course of a reverse flow situation. This protectionis provided by the second seal seat 124 a(2) and the encapsulated formof valve member 126 a providing a “bottom” disk member 128 a to seatagainst seal seat 124 a(2) and prevent such a reverse flow situation.

Moreover, the addition of the second seal seat 124 a(2) and “bottom”disk member 128 a associated with valve member 126 a has patientprotection applications as well. A reverse flow condition can occur, inone example, if a conventional stopcock is used to connect pressuretransducer P to isolation port 122 a. If the stopcock is provided with aport that could inadvertently be “opened” to atmospheric pressure, ahead pressure differential situation could arise in the fluid path 18resulting in reverse fluid flow in internal cavity 118 a therebypossibly introducing air via Y-T fitting 58 into the disposable firstsection 40 of the fluid path 18 and, possibly, to the patient. If such areverse flow situation arises, valve member 126 a moves in the reversedirection and closes against the second seal seat 124 a(2) andpreventing the reverse flow situation from developing.

As indicated previously, projections 140, 142 are un-encapsulated by thedisk member 128 a and this characteristic coupled with their extendedlength reaching into inlet port 120 a and isolation port 122 a permitsthe valve member 126 a to be placed into a bi-directional open state. InFIG. 7, cap member 143 is provided and includes a luer tip L. Luer tip Lextends sufficiently into isolation port 122 a to contact upperprojection 140 and, via this engagement or contact, unseat valve member126 a from seal seat 124 a. The presence of luer tip L in engagementwith projection 140 maintains the orientation of valve member 126 a in abi-directionally open position. As a result, saline or another flushingfluid may be introduced into inlet port 120 a and internal cavity 118 ato purge air bubbles from internal cavity 118 a and isolation port 122a. A three-way stopcock (not shown) may be secured to isolation port 122a after removal cap member 143 to provide a waste port to complete thepurging operation to atmospheric conditions as will be appreciated bythose skilled in the art, and, thereafter, pressure transducer P may beconnected via connecting tubing T to the stopcock. As an alternative, apre-purged pressure transducer arrangement may be secured to isolationport 122 a (after air purging thereof) without the interposing of astopcock.

A third embodiment of pressure isolation mechanism 100 b is shown inFIGS. 8-12. Pressure isolation mechanism 100 b operates in an analogousmanner to pressure isolation mechanisms 100, 100 a discussed hereinabovebut includes several structural differences over these embodiments.Initially, it is noted that housing body 102 b is still desirablyprovided as a two-piece structure including first or upper housingportion 104 b and second or lower housing portion 106 b, which areadapted to connect together to form the housing body 102 b. However,second or lower housing portion 106 b is now formed with a centralrecess 144 which is adapted to receive and accept a depending annularelement 146 associated with the first or upper housing portion 104 b.The insertion of annular element 146 within central recess 144 may beconfigured as a friction fit engagement to secure the connection firstand second housing portions 104 b, 106 b. In this embodiment, a suitablemedical grade adhesive is desirably used to secure the engagement ofannular element 146 within central recess 144. Other suitable connectingtechniques include solvent-based, laser, or ultrasonic welds. As will benoted from FIGS. 8-12, second or lower housing portion 106 b has agenerally cylindrical appearance while first or upper housing portion104 b forms a cap structure for the cylindrical second housing portion106 b. This change in outward appearance from pressure isolationmechanisms 100, 100 a does not affect the operation of pressureisolation mechanism 100 b.

First and second housing portions 104 b, 106 b of housing body 102 b,when secured together, define internal chamber or cavity 118 b ingenerally the same manner as discussed previously. Housing body 102 bfurther includes male-luer inlet port 120 b in the lower or secondhousing portion 106 b which communicates with internal cavity 118 b andfemale-luer isolation port 122 b in the first or upper housing portion104 b also in fluid communication with the internal cavity 118 b thesame manner as discussed previously. However, internal cavity 118 b ofhousing body 102 b is formed to accept a ball-shaped valve member 126 brather than the generally disk-shaped valve members 126, 126 a discussedpreviously. Ball valve member 126 b is again free-floating or freelymovable in internal cavity 118 b in response to fluid flow in inlet port120 a. By free-floating it is again generally meant that ball valvemember 126 b in this embodiment is freely movable within internal cavity118 b in response to fluid flow into inlet port 120 b so that the valvemember 126 b may engage and seal against a seal seat 124 b which is nowformed or defined by an inner surface 148 of first or upper housingportion 104 b of housing body 102 b. This free-floating movement mayinclude a rotational component in this embodiment.

As ball valve member 126 b seats and seals against inner surface 148 offirst housing portion 104 b and, in particular, seal seat 124 b formedby the inner surface 148, fluid flow through internal cavity 118 b isprevented thereby isolating isolation port 122. FIG. 11 illustrates an“open” state of pressure isolation mechanism 100 b wherein ball valvemember 126 b does not engage seal seat 124 b. It will be clear that ballvalve member 126 b is slightly smaller in diameter than the diameter ofinternal cavity 118 b which permits fluid communication between inletport 120 b and isolation port 122 b in the open state of pressureisolation mechanism 100 b as defined by ball valve member 126 b. Thisfluid communication is represented in FIG. 11 with reference character“C” which represents the clearance between the inner surface 136 b ofsecond or lower housing portion 106 b of housing body 120 b and theperimetric outer surface of ball valve member 126 b. In order to preventball valve member 126 b from closing against the inner surface 136 b ofthe second or lower housing portion 106 b of housing body 102 b, tabmembers or structures 134 b may also be provided in this embodiment. Aswith the structure of pressure isolation mechanism 100 a discussedpreviously, tab members or structures 134 b are formed on the innersurface 136 b of the second or lower housing portion 106 b of housingbody 102 b.

As indicated previously, in the open position or state of ball valvemember 126 b fluid communication is present between inlet port 120 b andisolation port 122 b due to the clearance C between the ball valvemember 126 b and the inner surface 136 b of the second or lower housingportion 106 b of housing body 102 b. This clearance C permitshemodynamic pressure signals to be transmitted to the pressuretransducer P through the fluid in internal cavity 118 b. Ball valvemember 126 b is also made of compliant material, such as rubbers orthermoplastic elastomers. Accordingly, in the closed position of ballvalve member 126 b, for example, when pressure isolation mechanism 100 bis inverted as described previously, the compliant material thatdesirably forms ball valve member 126 b allows hemodynamic pressuresignals to be transmitted through the body of the ball valve member 126b to the pressure transducer P. Thus, it is possible to take accuratehemodynamic pressure signal readings with pressure transducer P in theclosed and open positions or states of pressure isolation mechanism 100b as defined by ball valve member 126 b during conditions when a fluidinjection procedure is not ongoing. Nonetheless, pressure transducer Premains protected from damaging fluid pressure present at inlet port 120b when a fluid injection procedure commences due to the free-floating,flow-based sealing action of ball valve member 126 b.

A fourth embodiment of pressure isolation mechanism 100 c is shown inFIGS. 13-16. Pressure isolation mechanism 100 c operates in an analogousmanner to pressure isolation mechanisms 100, 100 a, 100 b discussedhereinabove and has the outward appearance of pressure isolationmechanism 100 b discussed immediately above. As with pressure isolationmechanism 110 b, housing body 102 c is desirably provided as a two-piecestructure including first or upper housing portion 104 c and second orlower housing portion 106 c, which are adapted to connect together toform the housing body 102 b. As with the immediately foregoingembodiment, second or lower housing portion 106 c is now formed withcentral recess 144 c which is adapted to receive and accept dependingannular element 146 c associated with the first or upper housing portion104 c. The engagement of annular element 146 c within central recess 144c may again be configured as a friction fit engagement to secure theconnection first and second housing portions 104 c, 106 c, with thisengagement secured by a suitable medical grade adhesive or othertechniques as outlined previously. As with pressure isolation mechanism100 b, second or lower housing portion 106 c has a generally cylindricalappearance while first or upper housing portion 104 c forms a capstructure for the cylindrical second housing portion 106 c. This changein outward appearance does not affect the operation of pressureisolation mechanism 100 c.

First and second housing portions 104 c, 106 c of housing body 102 c,when secured together, define internal chamber or cavity 118 c ingenerally the same manner as discussed previously. Housing body 102 cfurther includes male-luer inlet port 120 c in the second or lowerhousing 106 c which communicates with internal cavity 118 c andfemale-luer isolation port 122 c in the first or upper housing portion104 c also in fluid communication with the internal cavity 118 c. Asnoted previously, the male-female luer configurations may be reversed oninlet port 120 c and isolation port 122 c. In this embodiment, internalcavity 118 c of housing body 102 c is now elongated and shaped to accepta cylindrical valve member 126 c. Valve member 126 c is generallycylindrical-shaped with the cylinder-shaped valve member 126 c comprisedof disk member 128 c formed of compliant material, such as rubbers orthermoplastic elastomers or silicone as outlined previously, andstiffening element 130 c which is desirably integrally formed with diskmember 128 c or otherwise secured in permanent or semi-permanent fashionwith disk member 128 c such as by an adhesive, as discussed previously.Stiffening element 130 c is desirably formed of plastic materials asdetailed previously and has a generally cylindrical shape. Stiffeningelement 130 c is generally positioned in association with disk member128 c for supporting disk member 128 c to properly engage and seat withseal seat 124 c to seal inlet port 120 c from isolation port 122 c.Moreover, as with valve member 126 discussed previously, stiffeningelement 130 c is provided with tab members 134 c on its bottom side 132c facing inlet port 120 c which prevents the cylinder valve member 126 cfrom forming a complete seal with the interior or inner surface 136 c ofsecond or lower housing portion 106 c of housing body 102 c.

Cylinder valve member 126 c operates in generally the same manner asdisk-shaped valve member 126 discussed previously. Accordingly, cylindervalve member 126 c is generally responsive to fluid flow in inlet port120 c so that the valve member 126 c may seat and seal against seal seat124 c to form a closed state or condition of pressure isolationmechanism 100 c. When valve member 126 c is not seated against seal seat124 c, valve member 126 c defines the opens state or condition of thepressure isolation mechanism 100 c. Desirably, the fluid flow in inletport 120 c needed to cause valve member 126 c to seat and seal againstseal seat 124 c and thereby close the pressure isolation mechanism 100 cis very small and will seat and seal against seal seat 124 c in a nearstatically closed system due to very small compliance of the pressuretransducer P and connecting tubing T associated therewith connected toisolation port 122 c. This small volume capacitance generates reversefluid flow in isolation port 122 c and the upper portion of internalcavity 118 c that unseats valve member 126 c from seal seat 124 c whenfluid injections are not occurring thereby “opening” the pressureisolation mechanism 100 c, as described previously. Sufficient fluidflow is typically present in inlet port 120 c to seat and seal valvemember 126 c against seal seat 124 c when a fluid injection procedure isongoing using fluid injector 14 and syringe 32 and, when fluid injectionis complete, fluid flow ceases allowing valve member 126 c to unseatfrom seal seat 124 c due to the upstream volume capacitance associatedwith pressure transducer P and connecting tubing T and isolation port122 c.

Additionally, in the open position or state of valve member 126 c fluidcommunication is present between inlet port 120 c and isolation port 122c, as shown in FIG. 15, which permits hemodynamic pressure signals to betransmitted by fluid present in internal cavity 118 c to the pressuretransducer P associated with isolation port 122 c. In the closedposition of valve member 126 c, for example, when pressure isolationmechanism 100 b is inverted as described previously, wherein disk member128 c seats against seal seat 124 c, the compliant material thatdesirably forms disk member 128 c allows the hemodynamic pressuresignals to be transmitted through the body of valve member 126 c to thepressure transducer P. Thus, it is possible to take accurate hemodynamicpressure signal readings with pressure transducer P in the closed andopen positions or states of pressure isolation mechanism 100 c asdefined by valve member 126 c during conditions when a fluid injectionprocedure is not ongoing. Nonetheless, pressure transducer P remainsprotected from damaging fluid pressure present at inlet port 120 c whena fluid injection procedure commences due to the free-floating,flow-based sealing action of cylinder valve member 126 c.

Referring to FIGS. 17-23 another embodiment of pressure isolationmechanism 100 d is shown. As with previous embodiments, pressureisolation mechanism 100 d comprises a housing 102 d that be a unitaryhousing or, typically, a multi-piece housing including first or upperhousing portion 104 d and second or lower body portion 106 d, which areadapted to connect together in the manner described hereinabove inconnection with FIGS. 3-6 in particular. However, pressure isolationmechanism 100 d differs from previous embodiments in that housing body102 d is adapted to directly receive or accept fluid connection directlyto input lines 64, 66. As indicated previously, first input line 64 isassociated with the low pressure fluid delivery system 38 generally andthe output line 52 connected to the drip chamber 48 associated with thesecondary fluid source 36 in particular. Second input line 66 isassociated with the high pressurizing system or device comprised bysyringe 32 and fluid injector 14. Second or lower body portion 106 ddefines a primary or high pressure lumen 150, which forms a highpressure side of pressure isolation mechanism 100 d. An inlet port 152to high pressure or primary lumen 150 is in fluid communication with thesecond input line 66 which is the high pressure line connecting pressureisolation mechanism 100 d with the output line 54 associated withmulti-position valve 46 and, ultimately, syringe 32 associated withfluid injector 14. An outlet port 154 of lumen 150 is connected tosecond multi-position valve 72 by conventional medical connectionmethods.

First or upper housing portion 104 d of housing body 102 d defines asecondary or low pressure lumen 156 which generally forms a low pressureside of pressure isolation mechanism 100 d. Low pressure lumen 156 hasan inlet port 158 that is in fluid communication with first input line64, which is a low pressure line that connects pressure isolationmechanism 100 d to the low pressure fluid delivery system 38. The firstor upper housing portion 104 d of housing body 102 d further includes apressure isolation port 160 to which a pressure transducer P(illustrated in FIG. 2A) may be connected. Pressure isolation port 160may terminate in a luer connector for connecting pressure transducer Pto luer structure 162 associated with pressure isolation port 160.Pressure isolation port 160 is in fluid communication with low pressurelumen 156 and high pressure lumen 150 via internal cavity 118 d.

Internal cavity 118 d is formed by the first and second housing portions104 d, 106 d of housing body 102 d in generally the same manner aspressure isolation mechanism 100 discussed previously. First or upperhousing portion 104 d defines seal seat or rim 124 d internally withininternal cavity 118 d in generally the same manner as present inpressure isolation mechanism 100 discussed previously. Accordingly, sealseat 124 d is a raised continuous lip or rim against which valve member126 d may make a sealing connection or engagement. Seal seat 124 d isprovided in internal cavity 118 d between high pressure lumen 150 andlow pressure lumen 156 and isolation port 160. Valve member 126 d isformed in the same manner as valve member 126 discussed previously andis adapted to engage and seal against seal seat 124 d in generally thesame manner as discussed previously in connection, primarily, with FIGS.3-6. Accordingly, valve member 126 d is disposed within the internalcavity 118 d to be free-floating therein. However, valve member 126 d isnow responsive to fluid flow in high pressure lumen 150 and is freelymovable within internal cavity 118 d in response to fluid flow highpressure lumen 150 so that the valve member 126 d may engage and sealagainst seal seat 124 d to close off fluid flow through internal cavity118 d thereby isolating pressure isolation port 160 and secondary, lowpressure lumen 156.

Accordingly, in operation, valve member 126 d is generally responsive tofluid flow in high pressure lumen 150 so that the valve member 126 d mayseat and seal against seal seat 124 d to form a closed state orcondition of pressure isolation mechanism 100 d. When valve member 126 dis not seated against seal seat 124 d, valve member 126 d defines anopens state or condition of the pressure isolation mechanism 100 d.Desirably, the fluid flow in high pressure lumen 150 needed to causevalve member 126 d to seat and seal against seal seat 124 d and therebyclose the pressure isolation mechanism 100 d is very small and will seatand seal against seal seat 124 d in a near statically closed system dueto very small volumetric capacitance or compliance of the pressuretransducer P and connecting tubing T associated therewith connected topressure isolation port 160 and, further, the volumetric capacitance orcompliance of secondary lumen 156. This small volume capacitance orcompliance generates reverse fluid flow in pressure isolation port 160 dand internal cavity 118 d that unseats valve member 126 d from seal seat124 d when fluid injections are not occurring thereby “opening” thepressure isolation mechanism 100 d. As described previously, sufficientfluid flow is typically present in high pressure lumen 150 to seat andseal valve member 126 d against seal seat 124 d when a fluid injectionprocedure is ongoing using fluid injector 14 and syringe 32 and whenfluid injection is complete, fluid flow ceases allowing valve member 126d to unseat from seal seat 124 d due to the small volume capacitance orcompliance of the pressure transducer P and connecting tubing Tassociated therewith connected to pressure isolation port 160 and,further, the volumetric capacitance or compliance of secondary lumen156. As with valve member 126 d, stiffening element 130 d may have tabmembers 134 d on bottom side 132 d to prevent reverse closure of valvemember 126 d in the manner discussed previously in this disclosure.

Additionally, in the open position or state of valve member 126 d fluidcommunication is present between primary lumen 150 and secondary lumen156 and pressure isolation port 160, as shown in FIG. 19, which permitshemodynamic pressure signals to be transmitted to the pressuretransducer P associated with pressure isolation port 160 through fluidpresent within internal cavity 118 d. In the closed position of valvemember 126 d, for example, when pressure isolation mechanism 100 d isinverted as described previously, wherein disk member 128 d seatsagainst seal seat 124 d, the compliant material that desirably formsdisk member 128 d allows the hemodynamic pressure signals to betransmitted through the body of valve member 126 d to the pressuretransducer P. Thus, it is possible to take accurate hemodynamic pressuresignal readings with pressure transducer P in the closed and openpositions or states of pressure isolation mechanism 100 d as defined byvalve member 126 d during conditions when a fluid injection procedure isnot ongoing. Nonetheless, pressure transducer P remains protected fromdamaging fluid pressure present at inlet port 120 d when a fluidinjection procedure commences due to the free-floating, flow-basedsealing action of valve member 126 d.

FIGS. 21-24 illustrate a further aspect of pressure isolation mechanism100 d. Pressure isolation mechanism 100 d as configured to provideaccurate undamped hemodynamic pressure readings when saline is presentbetween the patient and the pressure transducer P associated withpressure isolation port 160. However, it is also desirable to provide anundamped signal when contrast is present between the patient and thepressure transducer P. Generally, hemodynamic pressure signals aredamped by the presence of air bubbles, thicker fluid media such ascontrast, medical tubing lengths, internal diameters, and overall systemand tubing compliance, as described previously. The variation ofpressure isolation mechanism 100 d illustrated in FIGS. 17-24significantly reduces the dampening of the hemodynamic pressure signalswhen contrast is present in internal cavity 118 d by substantiallyisolating the compliant tubing associated with the saline, low pressure“side” of the pressure isolation mechanism 100 d from the pressuretransducer P associated with pressure isolation port 160 d. This isaccomplished in one variation by substantially isolating the complianttubing and other upstream elements connected with low pressure orsecondary lumen 156 with a valve arrangement 2100 disposed in thislumen. Valve arrangement 2100, as will be clear from the followingdescription, allows fluid flow in two directions (bilaterally) in thesecondary lumen 156 carrying saline but fluid flow does not start untilpressures are above any blood pressure readings.

In general, in pressure isolation mechanism 100 d, outlet port 154 ofprimary lumen 150 is associated with a patient, inlet port 152 ofprimary lumen 150 is associated with syringe 32 and fluid injector 14,and inlet port 158 of secondary lumen 156 is associated with the lowpressure saline delivery system 38. Valve arrangement 2100 is generallyassociated with inlet port 158 of secondary lumen 156 and isolates the“compliant” system components of the low pressure saline fluid deliverysystem 38 from hemodynamic blood pressure signals from the patient. As aresult, these readings are substantially undamped and accurate readingmay be taken via a pressure transducer P associated with pressureisolation port 160.

Valve arrangement 2100 comprises an adaptor sleeve 2110 which is sizedfor mating engagement with the inlet portion or port 158 of secondarylumen 156. Adaptor sleeve 2110 may be an injection molded structure anddefines a lumen 2112 therethrough adapted to accept the medical tubingforming first input line 64, which may be adhesively secured in lumen2112. A stop 2114 is formed in lumen 2112 to limit insertion of firstinput line 64 in adaptor sleeve 2110. Adaptor sleeve 2110 secures a diskvalve 2116 in place within inlet port 158 and across secondary lumen156. Disk valve 2116 regulates fluid flow bi-laterally through secondarylumen 156 and desirably comprises a stamped disk valve member 2118 madefrom a flexible thermoplastic material that has one or more slits oropenings 2120 through the body of the disk valve member 2118. The numberof slits 2120 and length of the slits 2120 control the pressure neededto achieve fluid flow in both directions (bilaterally). Slit disk valvesachieve flow control by changing one or more of several design factorsas is well-known in the art. For example, slit or passageway openingpressure may be affected by choice of material for the disk valve member2118, number of slits 2120, length of slits 2120, freedom ofdeflection/deformation permitted in secondary lumen 156 and/or inletport 158, and diameter of the secondary lumen 156 and inlet port 158.

In operation, disk valve 2116 allows fluid flow in both directions andstop 2114 is typically spaced a short distance away from the disk valvemember 2118 to provide sufficient spacing or room to allow the diskvalve member 2118 to deflect or deform under fluid pressure wherebyslits 2120 open and allow fluid flow therethrough. On the opposite sideof the disk valve 2116, the secondary lumen 156 may be formed with ashoulder 2122 to restrain the movement or deflection of the disk valvemember 2118 in the secondary lumen 156. While the sandwiched arrangementof disk valve member 2118 between shoulder 2122 and stop 2114 may besufficient to fix the location of the disk valve 2116 in inlet port 158,it is desirable to use a medical grade adhesive around the periphery ofdisk valve member 2118 to secure the disk valve member 2118 in inletport 158 and across secondary lumen 156. If desired, a small in-lineporous filter valve 2119 may be provided in secondary lumen 156 to addback pressure to limit on pulsatile flow of peristaltic pump 26 and slowdown the initial burst of air and fluid when the disk valve 2116initially operates or opens. FIGS. 22A-22C illustrate disk valve member2118 with one, two, and three slits 2120, respectively, allow for thechanging of opening pressure for valve arrangement 2100. Stop 2114 isgenerally tapered to allow for the deflecting/deforming movement of diskvalve member 2118 in lumen 2112 during operation of disk valve 2118.Disk valve 2118 generally forms a “second” valve structure in pressureisolation mechanism 100 d in addition to the “first” valve structure inpressure isolation mechanism 100 d in the form of valve member 126 d.

As shown in FIGS. 23-24, sleeve adaptor 2110 is formed with a tubularbody portion 2124 that defines lumen 2112 and an integral annular collar2126 which extends along the outer side of the tubular body portion2124. Annular collar 2126 engages or receives the tubular portion ofsecond housing portion 106 of valve housing 1742 which defines thesecondary lumen 156 and inlet port 158. Annular collar 2126 defines anannular space 2128 for receiving the inlet port 158 defined by thetubular portion of the second housing portion 106 d of housing body 102d. Inlet port 158 may be secured in annular space 2128 via medical gradeadhesive and/or frictional engagement. As revealed by FIGS. 23-24 andFIG. 21, disk valve member 2118 may be formed with a continuous (oralternatively interrupted) recess or groove 2130 adapted to receive asingle continuous tab member 2132 (or multiple, discrete tab members2132) provided on a distal end 2134 of the tubular body portion 2124 ofthe sleeve adaptor 2110. This inter-engagement between the tab member2232 and the recess or groove 2130 in the disk valve member 2118 helpsto secure the engagement between disk valve 2116 and sleeve adaptor 2110in inlet port 158. The inter-engagement between the tab member 2232 andthe recess or groove 2130 in disk valve member 2118 may be supplementedwith a medical grade adhesive if desired.

A further embodiment of pressure isolation mechanism 100 e is shown inFIG. 25. Pressure isolation mechanism 100 e operates in an analogousmanner to pressure isolation mechanism 100 discussed hereinabove and hasthe same outward appearance of pressure isolation mechanism 100discussed immediately above. As a result, the following discussionrelating to pressure isolation mechanism 100 e will concentrate only thedifferences between pressure isolation mechanism 100 e and pressureisolation mechanism 100. In pressure isolation mechanism 100 e, avolumetric capacitance or compliance element 164 is disposed or added ininternal cavity 118 e. While volumetric capacitance element 164 is showndisposed in internal cavity 118 e, this element may be formed as part ofdisk member 128 e of valve member 126 e or be disposed in isolation port122 e or possibly be formed as part of upper housing portion 104 e anddisposed or oriented in internal cavity 118 e or isolation port 122 e.Volumetric capacitance element 164 is also desirably made of compliantmaterial and is provided to increase the volumetric capacitance orcompliance of the low pressure side of pressure isolation mechanism 100e upstream of (above) valve member 126 e thereby providing extracapacitance to initiate forward or reverse fluid flow in isolation port122 e and internal cavity 118 e to cause valve member 126 e to seat orunseat from seal seat 124 e. While volumetric capacitance element 164may be made of compliant material, it is desirably made of a cellular orporous material to be configured as a hollow member to allow compressionthereof and reduction in volume under fluid pressure in internal cavity118 e.

In FIG. 25, reference character D represents an exaggerated deformationof disk member 128 e of valve member 126 e resulting from fluid pressurein inlet port 120 e acting on valve member 126 e when a fluid injectionprocedure is ongoing and after the disk member 128 e has been moved intoengagement with seal seat 124 e. This deformation D occurs due to thecompliant nature of the material of disk member 128 e and causes diskmember D to deform into the upper portion of internal cavity 118 e. As aresult, the upper portion of internal cavity 118 e is reduced in volumeby the volume occupied by deformation D thereby increasing fluidpressure in the internal cavity 118 e. This increased fluid pressurelikewise acts on volumetric capacitance element 164 reducing its volumefrom an initial volume V.sub.1 to an exaggerated reduced volumeidentified with reference character V.sub.2. This change in volume“stores” volume capacitance or compliance that may be used to assist thegiven system compliance or capacitance in opening valve member 126 eafter the fluid injection procedure is completed. When the fluidinjection procedure is discontinued, fluid pressure acting on the bottomside 132 e of stiffening element 130 e is reduced and the disk member128 e resiliently returns to its normal state and the volumetriccapacitance element 164 expands to its normal volume thereby assistingin generating the reverse fluid flow in isolation port 122 e and theupper portion of internal cavity 118 e needed to unseat valve member 126e from seal seat 124 e to place the valve member 126 e in the openstate.

An additional embodiment of pressure isolation mechanism 100 f is shownin FIGS. 26-29. Pressure isolation mechanism 100 f is provided as partof disposable second section 42 of fluid path 18 (FIGS. 2A and 2B) inthe manner described previously in this disclosure and is associatedwith Y-T fitting 58 in a generally similar manner as describedpreviously in this disclosure. As with previously-described embodiments,pressure isolation mechanism 100 f serves several functions in fluiddelivery system 12 but is primarily provided to connect pressuretransducer P to fluid path 18 so that hemodynamic blood pressure signalreadings may be obtained during fluid delivery procedures involvingfluid delivery system 12. Further details of pressure isolationmechanism 100 f are provided hereinafter.

As described previously, Y-T fitting 58 includes two input ports 60, 62respectively connected to input lines 64, 66 as shown in FIG. 2Adiscussed previously. Y-T fitting 58 serves as the physical merge pointfor primary and secondary injection fluid paths for delivery of contrastand saline as examples to a patient via a catheter during a fluidinjection or delivery procedure. Input lines 64, 66 as discussedhereinabove comprise a first input line 64 associated with the lowpressure fluid delivery system 38 generally and output line 52 connectedto drip chamber 48 associated with secondary fluid source 36 inparticular, and a second input line 66 associated with high pressuresystem or device comprised by syringe 32 and fluid injector 14 (see FIG.2B). As further described previously, Y-T fitting 58 has a pressuretransducer port 68 and an outlet port 70.

Pressure isolation mechanism 100 f includes a housing body 102 fdefining an internal chamber or cavity 118 f therein which, in thisembodiment, is in direct fluid communication with and is formed in partby inlet port 120 f as shown in FIGS. 27-28. Inlet port 120 f is adaptedto engage or mate with pressure transducer port 68 on Y-T fitting 58 viathreaded or welded engagement in this embodiment. Accordingly, internalcavity 118 f is in substantially direct fluid communication withpressure transducer port 68 which allows fluid flow into internalchamber or cavity 118 f during a fluid injection procedure involvingfluid injector 14 and syringe 32. Housing body 102 f further comprisesor defines an isolation port 122 f similar to that described previouslyfor connection of pressure transducer P and tubing T associatedtherewith FIG. 2A and a branching flow initiating port 2200 associatedwith isolation port 122 f. As is apparent from FIGS. 27-28, isolationport 122 f is somewhat elongated to allow for connection of branchingflow initiating port 2200. Flow initiating port 2200 is in fluidcommunication with and positioned generally perpendicularly to isolationport 122 f. Isolation port 122 f may be formed as a standard luerconnector. In the illustrated embodiment, isolation port 122 f is shownas a female luer for exemplary purposes only and a male luer connectionmay be provided in place of the female luer if desired. Other connectionmethods may be used such as a bonded tube connection, customizedconnection, and the like. The illustration of luer-type fittings shouldnot be considered limiting in this disclosure.

Housing 102 f defines a primary seal seat or rim 124 f internally withininternal cavity 118 f that is generally circular (i.e., annular) inconfiguration but may take other suitable forms. Generally, seal seat124 f is a raised continuous lip or rim against which a valve element orstructure may make a sealing connection or engagement and performs thesame function as in previously discussed embodiments. Seal seat 124 f isprovided in internal cavity 118 f between inlet port 120 f and isolationport 122 f. In addition, a circular sealing rib or secondary seal seat2202 may also provided within internal cavity 118 f and is formed byhousing body 102 f radially outward and concentric to seal seat 124 f.As will be apparent from FIGS. 27-28, housing 102 f is a unitary body inthis embodiment which defines seal seat 124 f and secondary orstabilizing seal seat 2202 in opposition to valve member 126 f describedherein. Secondary or stabilizing seal seat 2202 aids seal seat 124 f informing a generally leak proof seal between housing 102 f and valvemember 126 f. Secondary seal seat 2202 is provided to enhance thesealing characteristics of the valve member 126 f and is optional.

Valve member 126 f is disposed within internal cavity 118 f betweeninlet port 120 f and isolation port 122 f. Valve member 126 f is adaptedto engage and seal against seal seat 124 f and secondary seal seat 2202but is disposed within the internal cavity 118 f to be free-floatingtherein. By free-floating it is generally meant that valve member 126 fis freely movable within internal cavity 118 f in response to fluid flowinto inlet port 120 f so that the valve member 126 f may engage and sealagainst at least seal seat 124 f to close-off fluid flow throughinternal cavity 118 f thereby isolating isolation port 122 f. Valvemember 126 f includes a generally unitary disk-shaped body formed ofcompliant material, such as rubbers, thermoplastic elastomers orsilicone. In contrast to previous embodiments, valve member 126 f is aunitary structure in this embodiment formed of resiliently deformablematerial (rubbers, thermoplastic elastomers or silicone as examples) anddoes not include a stiffening component or element but such a stiffeningstructure may be provided if desired. Valve member 126 f may be formedwith opposing projections 140 f, 142 f extending from top and bottomsides 131 f, 132 f, respectively, in a generally similar manner to valvemember 126 a discussed previously in connection with FIG. 7. Topprojection 140 f is substantially smaller than bottom projection 142 fand both projections 140 f, 142 f are now provided mainly as centeringstructures for centering valve member 126 f in internal cavity orchamber 118 f. However, in this embodiment top projection 140 f extendsthrough an aperture 2204 connecting internal cavity or chamber 118 fwith isolation port 122 f and bottom projection 142 f is now formed todepend into pressure transducer port 68 in Y-T connector 58 as shown inFIGS. 27-28. Moreover, a series of tab members 134 f are provided on thebottom side 132 f of valve member 126 f in this embodiment and whichprevent the valve member 126 f from collapsing onto pressure transducerport 68 and potentially forming a reverse seal with pressure transducerport 68.

Flow initiating port 2200 is connected with isolation port 122 f via abranch aperture 2206 and defines a branch chamber or lumen 2208connected to branch aperture 2206. Branch chamber or lumen 2208 isstepped as illustrated in FIGS. 27-28 to accommodate a flow initiatingmechanism 2210 therein. Flow initiating mechanism 2210 includes a flowinitiating member 2220 and a retainer member 2224; flow initiatingmember 2220 and retainer member 2224 are disposed, in sequence, inbranch chamber or lumen 2208. As illustrated in FIGS. 27-28, housing 102f and flow initiating port 2200 are desirably formed as a single,unitary member. Flow initiating member 2220 is held in place withinlumen 2208 by hollow retainer member 2222 positioned in the largerstepped portion of branch chamber or lumen 2208. An adhesive, solvent,laser, or ultrasonic weld may be used to maintain retainer member 2222within branch chamber or lumen 2208. Retainer member 2222 is hollow toreceive and support an air inlet prevention filter 2224. In particular,retainer member 2222 defines a hollow area or bore 2226 thataccommodates air inlet prevention filter 2224. Bore 2226 is connectedvia a connecting aperture 2228 to be open to branch chamber or lumen2208, with flow initiating member 2220 interposed between connectingaperture 2228 and branch aperture 2206. As shown in FIG. 29, connectingaperture 2228 may be bifurcated via a dividing member or segment 2229.Retainer member 2222 may be held in place in branch chamber or lumen2208 via any suitable joining method with the structure of flowinitiating port 2200 such as via adhesive, solvent, laser, or ultrasonicweld methods. As shown in FIGS. 27-28, a certain amount of clearance isprovided radially about flow initiating member 2220 and the inner wallof flow initiating port 2200 defining branch chamber or lumen 2208.Likewise, a certain amount of distal clearance 2230 is provided at thedistal end of filter 2224 and connecting apertures 2228 to allow fluidflow entering through connecting apertures 2228 to contact the materialforming filter 2224. Flow initiating member 2220 may be formed ofresiliently deformable material (rubbers, thermoplastic elastomers orsilicone as examples) and filter 2224 may be formed of porous materialssuch as porous polyethylene or porous polypropylene as non-limitingexamples.

Fluid initiating member 2220 is generally adapted to initiate a smallflow around valve member 126 f such that valve member 126 f operates toa closed position substantially upon flow initiation. Filter 2224 isconfigured such that when it is wetted with fluid passing around thebody of flow initiating member 2220, it prevents air from entering lumen2208 if fluid initiating member 2220 is somehow faulty. Additionally,when flow initiating member 2220 functions properly, filter 2224 isadapted to prevent an outward spray of fluid from a proximal end opening2232 in retainer member 2222. In normal operation, valve member 126 f isresponsive to fluid flow in inlet port 120 f so that the valve member126 f may seat and seal against at least seal seat 124 f to form aclosed state or condition of pressure isolation mechanism 100 f, asexplained in detail previously in this disclosure. When valve member 126f is not seated against seal seat 124 f, valve member 126 f defines anopen state or condition of the pressure isolation mechanism 100 fallowing hemodynamic pressure readings to be taken as desired viapressure transducer. Valve member 126 f is configured to isolatepressure transducer P and connecting tubing T associated therewithconnected to isolation port 122 from over pressure during pressureinjections involving fluid injector 14 and syringe 32.

In some instances, such as a low flow situation into internal cavity orchamber 118 f, insufficient flow may be present to cause valve member126 f to immediately displace to the closed position seated against atleast seal seat 124 f and typically also against secondary seal seat2202. Flow initiating member 2220 is adapted to provide sufficientupstream capacitance to allow a small flow of fluid to initiate aroundvalve member 126 f such that valve member 126 f operates to the closedposition substantially upon flow initiation. By sufficient it isgenerally meant that by virtue of the presence of flow initiatingmechanism 2210, enough capacitance is present upstream of valve member126 f to allow flow to initiate around the valve member 126 f andthereby operate the valve member 126 f to the closed position and viceversa (i.e., return to an open position). Flow initiating member 2220provides this sufficient upstream capacitance by displacing axially(compresses in an axial direction) in branch lumen 2208 which allowsfluid flow to commence about valve member 126 f, into isolation port 122f and through branch aperture 2206 into branch lumen 2208. This fluidpasses around the body of flow initiating member 2220 to enter bore 2226via connecting apertures 2228. Once fluid enters bore 2226, filter 2224becomes wetted and saturated with liquid. The presence of filter 2224prevents a spray of liquid from being ejected from the proximal endopening 2232 in retainer member 2222. Moreover, once wetted andsaturated with liquid, the surface tension of the liquid at a proximalend 2234 of filter 2224 prevents air from intruding into bore 2226 andbranch lumen 2208 which could potentially be withdrawn into internalcavity or chamber 118 f with attendant possibility of being injectedinadvertently into a patient.

In place of the open structure of flow initiating mechanism 2210described above, a closed (sealed) type structure could be implementedin accordance with the teachings of this disclosure. As an example shownin FIG. 30 of a pressure isolation mechanism 100 g, such a closedstructure could entail providing flow initiating mechanism 2210 g with abiasing spring 2250 which would provide the necessary upstreamcapacitance in generally the same operational manner discussedpreviously. In particular, it is envisioned that the biasing spring 2250would replace filter 2224 and be retained by the retainer member 2222 gprovided in a slightly different configuration. Biasing spring 2250 actsupon the flow initiating member 2220 g to provide the needed capacitancedescribed previously. It will be appreciated that the biasing spring2250 could be made as a resilient appendage integral to flow initiatingmember 2220 g. As FIG. 30 shows, a cylindrical retainer member 2222 g isdisposed in flow initiating port 2200 and is adapted to enclose both thebiasing spring 2250 and flow initiating member 2220 g and may bemaintained in flow initiating port 2200 by any of the joining methodsdescribed previously in this disclosure. A vent opening 2252 is providedfor venting bore 2226 g.

While several embodiments of a flow-based pressure isolation mechanismand fluid delivery system including flow-based pressure isolationtechniques and methods associated therewith were described in theforegoing detailed description, those skilled in the art may makemodifications and alterations to these embodiments without departingfrom the scope and spirit of the invention. Accordingly, the foregoingdescription is intended to be illustrative rather than restrictive. Theinvention described hereinabove is defined by the appended claims andall changes to the invention that fall within the meaning and the rangeof equivalency of the claims are embraced within their scope.

The invention claimed is:
 1. A fluid delivery system with flow-basedpressure isolation, the system comprising: a pressurizing device fordelivering injection fluid under pressure; a low pressure fluid deliverysystem; and a pressure isolation mechanism adapted for fluidcommunication with the pressurizing device and the low pressure fluiddelivery system, wherein the pressure isolation mechanism comprises: ahousing body defining an inlet port, an isolation port, a lumen in fluidcommunication with the isolation port, and an internal cavity, thehousing body further defining a seal seat in the internal cavity betweenthe inlet port and the isolation port; a valve member disposed in andfree floating in the internal cavity and adapted to engage the sealseat, wherein the valve member comprises an open position permittingfluid communication between the inlet port and the isolation port, andwherein the valve member is fluid flow responsive to fluid flow in theinlet port to engage the seal seat and attain a closed positionpreventing fluid communication between the inlet port and the isolationport; a flow initiating mechanism disposed in the lumen and in fluidcommunication with the isolation port, wherein the flow initiatingmechanism comprises a flow initiating member providing an upstreamvolume capacitance to initiate fluid flow in the isolation port actingupon the valve member such that the valve member operates to the closedposition when the flow initiating member stores an upstream volume ofthe upstream volume capacitance and operates to the open position whenthe flow initiating member releases the upstream volume; and a retainerenclosing and retaining the flow initiating mechanism within the lumenwithout capability of pressure relief venting the injection fluid toatmosphere.
 2. The fluid delivery system of claim 1, further comprising:a spring enclosed in the retainer to spring-bias the flow initiatingmember in the lumen.
 3. The fluid delivery system of claim 2, whereinthe retainer is cylindrical to enclose both the spring and the flowinitiating member.
 4. The fluid delivery system of claim 2, wherein thespring comprises a resilient appendage integral to the flow initiatingmember.
 5. The fluid delivery system of claim 1, further comprising: apressure transducer associated with the isolation port.
 6. The fluiddelivery system of claim 1, wherein the valve member is formed of acompliant material.
 7. The fluid delivery system of claim 6, wherein thecompliant material is selected to transmit hemodynamic pressure signalsthrough the valve member to a pressure transducer associated with theisolation port.
 8. The fluid delivery system of claim 1, wherein theinlet port is in fluid communication with the pressurizing device andthe low pressure fluid delivery system via a fitting.
 9. The fluiddelivery system of claim 8, wherein the fitting defines a first inputport in fluid communication with the pressurizing device, a second inputport in fluid communication with the low pressure fluid delivery system,an outlet port, and a pressure transducer port in fluid communicationwith the inlet port of the pressure isolation mechanism.
 10. The fluiddelivery system of claim 1, further comprising: an air inlet preventionfilter disposed in a bore defined in the retainer and adapted to preventair from entering the internal cavity when the filter is wetted withfluid.
 11. The fluid delivery system of claim 10, wherein the upstreamvolume capacitance is provided by the flow initiating member beingadapted to resiliently compress in an axial direction within the lumento thereby allow fluid to pass around the flow initiating member andinto contact with the air inlet prevention filter.
 12. A pressureisolation mechanism, comprising: a housing body defining an inlet port,an isolation port, a lumen in fluid communication with the isolationport, and an internal cavity, the housing body further defining a sealseat in the internal cavity between the inlet port and the isolationport; a valve member disposed in and free floating in the internalcavity and adapted to engage the seal seat, wherein the valve membercomprises an open position permitting fluid communication between theinlet port and the isolation port, and wherein the valve member is fluidflow responsive to fluid flow in the inlet port to engage the seal seatand attain a closed position preventing fluid communication between theinlet port and the isolation port; a flow initiating mechanism disposedin the lumen and in fluid communication with the isolation port, whereinthe flow initiating mechanism comprises a flow initiating memberproviding an upstream volume capacitance to initiate fluid flow in theisolation port acting upon the valve member such that the valve memberoperates to the closed position when the flow initiating member storesan upstream volume of the upstream volume capacitance and operates tothe open position when the flow initiating member releases the upstreamvolume; and a retainer enclosing and retaining the flow initiatingmechanism within the lumen without capability of pressure relief ventingthe injection fluid to atmosphere.
 13. The pressure isolation mechanismof claim 12, further comprising: a spring enclosed in the retainer tospring-bias the flow initiating member in the lumen.
 14. The pressureisolation mechanism of claim 13, wherein the retainer is cylindrical toenclose both the spring and the flow initiating member.
 15. The pressureisolation mechanism of claim 13, wherein the spring comprises aresilient appendage integral to the flow initiating member.
 16. Thepressure isolation mechanism of claim 12, further comprising: a pressuretransducer associated with the isolation port.
 17. The pressureisolation mechanism of claim 12, wherein the valve member is formed of acompliant material.
 18. The pressure isolation mechanism of claim 17,wherein the compliant material is selected to transmit hemodynamicpressure signals through the valve member to a pressure transducerassociated with the isolation port.
 19. The pressure isolation mechanismof claim 12, further comprising: an air inlet prevention filter disposedin a bore defined in the retainer and adapted to prevent air fromentering the internal cavity when the filter is wetted with fluid. 20.The pressure isolation mechanism of claim 19, wherein the upstreamvolume capacitance is provided by the flow initiating member beingadapted to resiliently compress in an axial direction within the lumento thereby allow fluid to pass around the flow initiating member andinto contact with the air inlet prevention filter.